\documentclass[landscape,semhelv]{seminar}
\usepackage{verbatim}
-\usepackage[german]{babel}
+\usepackage[greek,german]{babel}
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
%\renewcommand{\familydefault}{\sfdefault}
%\usepackage{mathptmx}
+\usepackage{upgreek}
+
\begin{document}
\extraslideheight{10in}
\vspace{08pt}
- 13. November 2008
+ 20. November 2008
\end{center}
\end{slide}
\item hohe mechanische Stabilit"at
\item gute Ladungstr"agermobilit"at
\item sp"ate S"attigung der Elektronen-Driftgeschwindigkeit
+ \item hohe Durchbruchfeldst"arke
\item chemisch inerte Substanz
\item hohe thermische Leitf"ahigkeit und Stabilit"at
\item geringer Neutroneneinfangquerschnitt
Anwendungen:
\begin{itemize}
- \item Hochfrequenz-, Hochtemperatur und Hochleistungsbauelemente
- \item blaue LEDs
+ \item Hochfrequenz-, Hochtemperatur- und Hochleistungsbauelemente
+ \item Optoelektronik (blaue LEDs), Sensoren
\item Kandidat f"ur Tr"ager und W"ande in Fusionsreaktoren
- \item Luft- und Raumfahrtindistrie, Milit"ar
+ \item Luft- und Raumfahrtindustrie, Milit"ar
\item kohlenfaserverst"arkte SiC-Verbundkeramik
\end{itemize}
}
- \begin{picture}(0,0)(-275,-150)
- \includegraphics[width=4cm]{sic_inverter_ise.eps}
+ \begin{picture}(0,0)(-280,-150)
+ %\includegraphics[width=4cm]{sic_inverter_ise.eps}
\end{picture}
- \begin{picture}(0,0)(-275,-20)
- \includegraphics[width=4cm]{cc_sic_brake_dlr.eps}
+ \begin{picture}(0,0)(-280,-20)
+ %\includegraphics[width=4cm]{cc_sic_brake_dlr.eps}
\end{picture}
\end{slide}
+\begin{slide}
+
+ {\large\bf
+ Motivation
+ }
+
+ \vspace{4pt}
+
+ SiC - \emph{Born from the stars, perfected on earth.}
+
+ \vspace{4pt}
+
+ Herstellung d"unner SiC-Filme:
+ \begin{itemize}
+ \item modifizierter Lely-Prozess
+ \begin{itemize}
+ \item Impfkristall mit $T=2200 \, ^{\circ} \text{C}$
+ \item umgeben von polykristallinen SiC mit
+ $T=2400 \, ^{\circ} \text{C}$
+ \end{itemize}
+ \item CVD Homoepitaxie
+ \begin{itemize}
+ \item 'step controlled epitaxy' auf 6H-SiC-Substrat
+ \item C$_3$H$_8$/SiH$_4$/H$_2$ bei $1500 \, ^{\circ} \text{C}$
+ \item Winkel $\rightarrow$ 3C/6H/4H-SiC
+ \item hohe Qualit"at aber limitiert durch\\
+ Substratgr"o"se
+ \end{itemize}
+ \item CVD/MBE Heteroepitaxie von 3C-SiC auf Si
+ \begin{itemize}
+ \item 2 Schritte: Karbonisierung und Wachstum
+ \item $T=650-1050 \, ^{\circ} \text{C}$
+ \item Qualit"at/Gr"o"se noch nicht ausreichend
+ \end{itemize}
+ \end{itemize}
+
+ \begin{picture}(0,0)(-245,-50)
+ \includegraphics[width=5cm]{6h-sic_3c-sic.eps}
+ \end{picture}
+ \begin{picture}(0,0)(-240,-35)
+ \begin{minipage}{5cm}
+ {\scriptsize
+ NASA: 6H-SiC LED und 3C-SiC LED\\[-6pt]
+ nebeneinander auf 6H-SiC-Substrat
+ }
+ \end{minipage}
+ \end{picture}
+
+\end{slide}
+
\begin{slide}
{\large\bf
Motivation
}
- Problem:
+ \vspace{8pt}
- However, in order to become economically viable, several critical materials and processing issues still need to be solved. The most serious issue is the immature state of the crystal growth technology, where increases in wafer size and quality are urgently needed.
+ 3C-SiC (\foreignlanguage{greek}{b}-SiC) /
+ 6H-SiC (\foreignlanguage{greek}{a}-SiC)
+ \begin{itemize}
+ \item h"ohere Ladungstr"agerbeweglichkeit in \foreignlanguage{greek}{b}-SiC
+ \item h"ohere Durchbruchfeldst"arke in \foreignlanguage{greek}{b}-SiC
+ \item Micropipes (makroskopischer Bereich an Fehlstellen bis hin zur
+ Oberfl"ache) entlang c-Richtung
+ bei \foreignlanguage{greek}{a}-SiC
+ \item gro"sfl"achige epitaktische \foreignlanguage{greek}{a}-SiC-Herstellung
+ sehr viel weiter fortgeschritten verglichen mit der von 3C-SiC
+ \end{itemize}
- Und andersrum:
+ \vspace{16pt}
- Modifikation der Bandl"ucke und Spannungen in Heterostrukturen
+ {\color{blue}
+ \begin{center}
+ Genaues Verst"andnis des 3C-SiC-Ausscheidungsvorganges\\
+ $\Downarrow$\\
+ Grundlage f"ur technologischen Fortschritt in 3C-SiC-D"unnschichtherstellung
+ \end{center}
+ }
- Kein SiC-Ausscheidungsvorgang erw"unscht!
+ \vspace{16pt}
- {\tiny
- [1] J. H. Edgar, J. Mater. Res. 7 (1992) 235.}\\
- {\tiny
- [2] J. W. Strane, S. R. Lee, H. J. Stein, S. T. Picraux,
- J. K. Watanabe, J. W. Mayer, J. Appl. Phys. 79 (1996) 637.}
+ Grundlage zur Vermeidung von SiC-Ausscheidungen in
+ $\text{Si}_{\text{1-y}}\text{C}_{\text{y}}$ Legierungen
+ \begin{itemize}
+ \item Ma"sschneidern der elektronischen Eigenschaften von Si
+ \item gestreckte Heterostrukturen
+ \end{itemize}
\end{slide}
-\end{document}
+\begin{slide}
+
+ {\large\bf
+ Motivation
+ }
+
+ Die Alternative: Ionenstrahlsynthese
+
+ {\small
+
+ \begin{itemize}
+ \item Implantation 1:
+ 180 keV C$^+\rightarrow$ FZ-Si(100),
+ $D=7.9 \times 10^{17}$ cm$^{-2}$,
+ $T_{\text{i}}=500 \, ^{\circ} \text{C}$\\
+ epitaktisch orientierte 3C-SiC Ausscheidungen
+ in kastenf"ormigen Bereich,\\
+ eingeschlossen in a-Si:C
+ \item Implantation 2:
+ 180 keV C$^+\rightarrow$ FZ-Si(100),
+ $D=0.6 \times 10^{17}$ cm$^{-2}$,
+ $T_{\text{i}}=250 \, ^{\circ} \text{C}$\\
+ Zerst"orung einzelner SiC Ausscheidungen
+ in gr"o"ser werdenden amorphen Grenzschichten
+ \item Tempern:
+ $T=1250 \, ^{\circ} \text{C}$, $t=10\text{ h}$\\
+ Homogene st"ochiometrische 3C-SiC Schicht mit
+ scharfen Grenzfl"achen
+ \end{itemize}
+
+ \begin{minipage}{6.3cm}
+ \includegraphics[width=6.3cm]{ibs_3c-sic.eps}
+ \end{minipage}
+ \hspace*{0.2cm}
+ \begin{minipage}{6.5cm}
+ \vspace*{2.3cm}
+ {\scriptsize
+ Querschnitts-TEM-Aufnahme einer einkristallinen vergrabenen
+ 3C-SiC-Schicht.\\
+ (a) Hellfeldaufnahme\\
+ (b) 3C-SiC(111) Dunkelfeldaufnahme\\
+ }
+ \end{minipage}
+
+ \vspace{0.2cm}
+
+ Entscheidende Parameter: Dosis und Implantationstemperatur
+
+}
+
+\end{slide}
\begin{slide}
{\large\bf
- Crystalline silicon and cubic silicon carbide
+ SiC-Ausscheidungsvorgang
}
\vspace{8pt}
- {\bf Lattice types and unit cells:}
+ {\bf Kristallstruktur und Einheitszelle:}
\begin{itemize}
- \item Crystalline silicon (c-Si) has diamond structure\\
- $\Rightarrow {\color{si-yellow}\bullet}$ and
- ${\color{gray}\bullet}$ are Si atoms
- \item Cubic silicon carbide (3C-SiC) has zincblende structure\\
- $\Rightarrow {\color{si-yellow}\bullet}$ are Si atoms,
- ${\color{gray}\bullet}$ are C atoms
+ \item kristallines Silizium (c-Si): Diamantstruktur\\
+ ${\color{si-yellow}\bullet}$ und ${\color{gray}\bullet}$
+ $\leftarrow$ Si-Atome
+ \item kubisches SiC (3C-SiC): Zinkblende-Struktur\\
+ ${\color{si-yellow}\bullet} \leftarrow$ Si-Atome\\
+ ${\color{gray}\bullet} \leftarrow$ C-Atome
\end{itemize}
\vspace{8pt}
\begin{minipage}{8cm}
- {\bf Lattice constants:}
+ {\bf Gitterkonstanten:}
\[
4a_{\text{c-Si}}\approx5a_{\text{3C-SiC}}
\]
- {\bf Silicon density:}
+ {\bf Siliziumdichten:}
\[
\frac{n_{\text{3C-SiC}}}{n_{\text{c-Si}}}=97,66\,\%
\]
\end{slide}
- \small
\begin{slide}
{\large\bf
- Supposed Si to 3C-SiC conversion
+ SiC-Ausscheidungsvorgang
+ }
+
+ Hochaufl"osungs-TEM:\\[-0.5cm]
+
+ \begin{minipage}{3.3cm}
+ \includegraphics[width=3.3cm]{tem_c-si-db.eps}
+ \end{minipage}
+ \begin{minipage}{9cm}
+ Bereich oberhalb des Implantationsmaximums\\
+ Wolkenstruktur "uberlagert auf ungest"orten Si-Muster\\
+ $\rightarrow$ C-Si Dumbbells
+ \end{minipage}
+ \begin{minipage}{3.3cm}
+ \includegraphics[width=3.3cm]{tem_3c-sic.eps}
+ \end{minipage}
+ \begin{minipage}{9cm}
+ Bereich ums Implantationsmaximum\\
+ Moir\'e-Kontrast-Muster\\
+ $\rightarrow$ inkoh"arente 3C-SiC-Ausscheidungen in c-Si-Matrix
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ SiC-Ausscheidungsvorgang
}
\small
+
\vspace{6pt}
- Supposed conversion mechanism of heavily carbon doped Si into SiC:
+ Vermuteter 3C-SiC-Ausscheidungsvorgang in c-Si:
\vspace{8pt}
\vspace{8pt}
\begin{minipage}{3.8cm}
- Formation of C-Si dumbbells on regular c-Si lattice sites
+ Bildung von C-Si Dumbbells auf regul"aren c-Si Gitterpl"atzen
\end{minipage}
\hspace{0.6cm}
\begin{minipage}{3.8cm}
- Agglomeration into large clusters (embryos)\\
+ Anh"aufung hin zu gro"sen Clustern (Embryos)\\
\end{minipage}
\hspace{0.6cm}
\begin{minipage}{3.8cm}
- Precipitation of 3C-SiC + Creation of interstitials\\
+ Ausscheidung von 3C-SiC + Erzeugung von Si-Zwischengitteratomen
\end{minipage}
\vspace{12pt}
- \begin{minipage}{7cm}
- Experimentally observed [3]:
+ Aus experimentellen Untersuchungen:
\begin{itemize}
- \item Minimal diameter of precipitation: 4 - 5 nm
- \item Equal orientation of Si and SiC (hkl)-planes
+ \item kritischer Durchmesser einer Ausscheidung: 4 - 5 nm
+ \item gleiche Orientierung der c-Si and 3C-SiC (hkl)-Ebenen
\end{itemize}
- \end{minipage}
- \begin{minipage}{6cm}
- \vspace{32pt}
- \hspace{16pt}
- {\tiny [3] J. K. N. Lindner, Appl. Phys. A 77 (2003) 27.}
- \end{minipage}
\end{slide}
\begin{slide}
{\large\bf
- Simulation details
+ Details der MD-Simulation
}
+ \vspace{12pt}
\small
- {\bf MD basics:}
+ {\bf MD-Grundlagen:}
\begin{itemize}
- \item Microscopic description of N particle system
- \item Analytical interaction potential
- \item Hamilton's equations of motion as propagation rule\\
- in 6N-dimensional phase space
- \item Observables obtained by time or ensemble averages
+ \item Mikroskopische Beschreibung eines N-Teilchensystems
+ \item Analytisches Wechselwirkungspotential
+ \item Numerische Integration der Newtonschen Bewegungsgleichung\\
+ als Propagationsvorschrift im 6N-dimensionalen Phasenraum
+ \item Observablen sind die Zeit- und/oder Ensemblemittelwerte
\end{itemize}
- {\bf Application details:}
+ {\bf Details der Simulation:}
\begin{itemize}
- \item Integrator: Velocity Verlet, timestep: $1\text{ fs}$
- \item Ensemble: isothermal-isobaric NPT [4]
+ \item Integration: Velocity Verlet, Zeitschritt: $1\text{ fs}$
+ \item Ensemble: NpT, isothermal-isobares Ensemble
\begin{itemize}
- \item Berendsen thermostat:
+ \item Berendsen Thermostat:
$\tau_{\text{T}}=100\text{ fs}$
- \item Brendsen barostat:\\
+ \item Berendsen Barostat:\\
$\tau_{\text{P}}=100\text{ fs}$,
$\beta^{-1}=100\text{ GPa}$
\end{itemize}
- \item Potential: Tersoff-like bond order potential [5]
+ \item Potential: Tersoff-"ahnliches 'bond order' Potential
+ \vspace*{12pt}
\[
E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad
\pot_{ij} = f_C(r_{ij}) \left[ f_R(r_{ij}) + b_{ij} f_A(r_{ij}) \right]
\]
\end{itemize}
- {\tiny
- [4] L. Verlet, Phys. Rev. 159 (1967) 98.}\\
- {\tiny
- [5] P. Erhart and K. Albe, Phys. Rev. B 71 (2005) 35211.}
- \begin{picture}(0,0)(-240,-70)
+ \begin{picture}(0,0)(-230,-30)
\includegraphics[width=5cm]{tersoff_angle.eps}
\end{picture}
\begin{slide}
{\large\bf
- Simulation sequence
+ Zwischengitter-Konfigurationen
}
\vspace{8pt}
- Interstitial configurations:
+ Simulationssequenz:\\
\vspace{8pt}
\rput(3.5,7){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
\parbox{7cm}{
\begin{itemize}
- \item Initial configuration: $9\times9\times9$ unit cells Si
- \item Periodic boundary conditions
+ \item initiale Konfiguration:\\
+ $9\times9\times9$ Einheitszellen c-Si
+ \item periodische Randbedingungen
\item $T=0\text{ K}$, $p=0\text{ bar}$
\end{itemize}
}}}}
\rput(3.5,3.5){\rnode{insert}{\psframebox{
\parbox{7cm}{
- Insertion of C / Si atom:
+ Einf"ugen der C/Si Atome:
\begin{itemize}
- \item $(0,0,0)$ $\rightarrow$ {\color{red}tetrahedral}
+ \item $(0,0,0)$ $\rightarrow$ {\color{red}tetraedrisch}
(${\color{red}\triangleleft}$)
\item $(-1/8,-1/8,1/8)$ $\rightarrow$ {\color{green}hexagonal}
(${\color{green}\triangleright}$)
\item $(-1/8,-1/8,-1/4)$, $(-1/4,-1/4,-1/4)$\\
- $\rightarrow$ {\color{magenta}110 dumbbell}
+ $\rightarrow$ {\color{magenta}110 Dumbbell}
(${\color{magenta}\Box}$,$\circ$)
- \item random positions (critical distance check)
+ \item zuf"allige Position (Minimalabstand)
\end{itemize}
}}}}
\rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
\parbox{3.5cm}{
- Relaxation time: $2\, ps$
+ Relaxation ($>2$ ps)
}}}}
\ncline[]{->}{init}{insert}
\ncline[]{->}{insert}{cool}
\begin{slide}
{\large\bf
- Results
- } - Si self-interstitial runs
+ Zwischengitter-Konfigurationen
+ }
\small
\begin{minipage}[t]{4.3cm}
- \underline{Tetrahedral}\\
+ \underline{Tetraedrisch}\\
$E_f=3.41$ eV\\
\includegraphics[width=3.8cm]{si_self_int_tetra_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
- \underline{110 dumbbell}\\
+ \underline{110 Dumbbell}\\
$E_f=4.39$ eV\\
\includegraphics[width=3.8cm]{si_self_int_dumbbell_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
\underline{Hexagonal} \hspace{4pt}
\href{../video/si_self_int_hexa.avi}{$\rhd$}\\
- $E_f^{\star}\approx4.48$ eV (unstable!)\\
+ $E_f^{\star}\approx4.48$ eV (nicht stabil!)\\
\includegraphics[width=3.8cm]{si_self_int_hexa_0.eps}
\end{minipage}
- \underline{Random insertion}
+ \underline{zuf"allige Positionen}
\begin{minipage}{4.3cm}
$E_f=3.97$ eV\\
\begin{slide}
{\large\bf
- Results
- } - Carbon interstitial runs
+ Zwischengitter-Konfigurationen
+ }
\small
\begin{minipage}[t]{4.3cm}
- \underline{Tetrahedral}\\
+ \underline{Tetraedrisch}\\
$E_f=2.67$ eV\\
\includegraphics[width=3.8cm]{c_in_si_int_tetra_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
- \underline{110 dumbbell}\\
+ \underline{110 Dumbbell}\\
$E_f=1.76$ eV\\
\includegraphics[width=3.8cm]{c_in_si_int_dumbbell_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
\underline{Hexagonal} \hspace{4pt}
\href{../video/c_in_si_int_hexa.avi}{$\rhd$}\\
- $E_f^{\star}\approx5.6$ eV (unstable!)\\
+ $E_f^{\star}\approx5.6$ eV (nicht stabil!)\\
\includegraphics[width=3.8cm]{c_in_si_int_hexa_0.eps}
\end{minipage}
- \underline{Random insertion}
+ \underline{zuf"allige Positionen}
\footnotesize
$E_f=0.47$ eV\\
\includegraphics[width=3.3cm]{c_in_si_int_001db_0.eps}
\begin{picture}(0,0)(-15,-3)
- 100 dumbbell
+ 100 Dumbbell
\end{picture}
\end{minipage}
\begin{minipage}[t]{3.3cm}
\begin{slide}
{\large\bf
- Results
- } - <100> dumbbell configuration
+ Zwischengitter-Konfigurationen
+ }
+
+ Das 100 Dumbbell
\vspace{8pt}
\small
- \begin{minipage}{4cm}
+ \begin{minipage}{5.5cm}
\begin{itemize}
\item $E_f=0.47$ eV
- \item Very often observed
- \item Most energetically\\
- favorable configuration
- \item Experimental\\
- evidence [6]
+ \item sehr h"aufig beobachtet
+ \item energetisch g"unstigste\\ Konfiguration
+ \item experimentelle und theoretische Hinweise
+ f"ur die Existenz dieser Konfiguration
\end{itemize}
- \vspace{24pt}
- {\tiny
- [6] G. D. Watkins and K. L. Brower,\\
- Phys. Rev. Lett. 36 (1976) 1329.
- }
+ \includegraphics[width=5.6cm]{c_in_si_100.ps}
\end{minipage}
- \begin{minipage}{8cm}
- \includegraphics[width=9cm]{100-c-si-db_s.eps}
+ \begin{minipage}{7cm}
+ \includegraphics[width=8cm]{100-c-si-db_s.eps}
\end{minipage}
\end{slide}
\begin{slide}
{\large\bf
- Simulation sequence
+ Simulationen zum Ausscheidungsvorgang
}
\small
\vspace{8pt}
- SiC precipitation simulations:
+ Simulationssequenz:\\
\vspace{8pt}
\begin{pspicture}(0,0)(12,8)
% nodes
- \rput(3.5,6.5){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
+ \rput(3.5,7.0){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
\parbox{7cm}{
\begin{itemize}
- \item Initial configuration: $31\times31\times31$ unit cells Si
- \item Periodic boundary conditions
+ \item initiale Konfiguration:\\
+ $31\times31\times31$ c-Si Einheitszellen
+ \item periodsche Randbedingungen
\item $T=450\, ^{\circ}\text{C}$, $p=0\text{ bar}$
- \item Equilibration of $E_{kin}$ and $E_{pot}$
+ \item "Aquilibrierung von $E_{\text{kin}}$ and $E_{\text{pot}}$
\end{itemize}
}}}}
\rput(3.5,3.2){\rnode{insert}{\psframebox[fillstyle=solid,fillcolor=lachs]{
\parbox{7cm}{
- Insertion of 6000 carbon atoms at constant\\
- temperature into:
+ Einf"ugen von 6000 C-Atomen\\
+ bei konstanter Temperatur
\begin{itemize}
- \item Total simulation volume {\pnode{in1}}
- \item Volume of minimal SiC precipitation {\pnode{in2}}
- \item Volume of necessary amount of Si {\pnode{in3}}
+ \item gesamte Simulationsvolumen {\pnode{in1}}
+ \item Volumen einer minimal SiC-Ausscheidung {\pnode{in2}}
+ \item Bereich der ben"otigten Si-Atome {\pnode{in3}}
\end{itemize}
}}}}
\rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
- \parbox{3.5cm}{
- Cooling down to $20\, ^{\circ}C$
+ \parbox{5.0cm}{
+ Nach 100 ps abk"uhlen auf $20\, ^{\circ}\textrm{C}$
}}}}
\ncline[]{->}{init}{insert}
\ncline[]{->}{insert}{cool}
\psframe[fillstyle=solid,fillcolor=white](7.5,1.8)(13.5,7.8)
\psframe[fillstyle=solid,fillcolor=lightgray](9,3.3)(12,6.3)
\psframe[fillstyle=solid,fillcolor=gray](9.25,3.55)(11.75,6.05)
- \rput(7.9,4.8){\pnode{ins1}}
- \rput(9.22,4.4){\pnode{ins2}}
- \rput(10.5,4.8){\pnode{ins3}}
+ \rput(7.9,4.2){\pnode{ins1}}
+ \rput(9.22,3.5){\pnode{ins2}}
+ \rput(11.0,3.8){\pnode{ins3}}
\ncline[]{->}{in1}{ins1}
\ncline[]{->}{in2}{ins2}
\ncline[]{->}{in3}{ins3}
\begin{slide}
{\large\bf
- Results
- } - SiC precipitation runs
-
+ Simulationen zum Ausscheidungsvorgang
+ }
\includegraphics[width=6.3cm]{pc_si-c_c-c.eps}
\includegraphics[width=6.3cm]{pc_si-si.eps}
- \begin{minipage}[t]{6.3cm}
- \tiny
- \begin{itemize}
- \item C-C peak at 0.15 nm similar to next neighbour distance of graphite
- or diamond\\
- $\Rightarrow$ Formation of strong C-C bonds
- (almost only for high C concentrations)
- \item Si-C peak at 0.19 nm similar to next neighbour distance in 3C-SiC
- \item C-C peak at 0.31 nm equals C-C distance in 3C-SiC\\
- (due to concatenated, differently oriented
- <100> dumbbell interstitials)
- \item Si-Si shows non-zero g(r) values around 0.31 nm like in 3C-SiC\\
- and a decrease at regular distances\\
- (no clear peak,
- interval of enhanced g(r) corresponds to C-C peak width)
- \end{itemize}
- \end{minipage}
- \begin{minipage}[t]{6.3cm}
- \tiny
- \begin{itemize}
- \item Low C concentration (i.e. $V_1$):
- The <100> dumbbell configuration
- \begin{itemize}
- \item is identified to stretch the Si-Si next neighbour distance
- to 0.3 nm
- \item is identified to contribute to the Si-C peak at 0.19 nm
- \item explains further C-Si peaks (dashed vertical lines)
- \end{itemize}
- $\Rightarrow$ C atoms are first elements arranged at distances
- expected for 3C-SiC\\
- $\Rightarrow$ C atoms pull the Si atoms into the right
- configuration at a later stage
- \item High C concentration (i.e. $V_2$ and $V_3$):
- \begin{itemize}
- \item High amount of damage introduced into the system
- \item Short range order observed but almost no long range order
- \end{itemize}
- $\Rightarrow$ Start of amorphous SiC-like phase formation\\
- $\Rightarrow$ Higher temperatures required for proper SiC formation
- \end{itemize}
- \end{minipage}
+ \vspace{-0.1cm}
+
+ \footnotesize
+ \underline{C-C, 0.15 nm}:\\
+ NN-Abstand in Graphit/Diamant\\
+ $\Rightarrow$ starke C-C Bindungen bei hohen Konz.\\
+ \underline{Si-C, 0.19 nm}:\\
+ NN-Abstand in 3C-SiC\\
+ \underline{C-C, 0.31 nm}:\\
+ C-C Abstand in 3C-SiC\\
+ vekettete, verschieden orientierte 100 C-Si DBs\\
+ \underline{Si-Si, $\sim$ 0.31 nm}:\\
+ g(r) erh"oht, Si-Si in 3C-SiC\\
+ Intervall entspricht C-C Peakbreite\\
+ Abfall bei regul"aren Abst"anden
+
+ \begin{picture}(0,0)(-175,-40)
+ \includegraphics[width=4.0cm]{conc_100_c-si-db_02.eps}
+ \end{picture}
+ \begin{picture}(0,0)(-278,-10)
+ \includegraphics[width=4.0cm]{conc_100_c-si-db_01.eps}
+ \end{picture}
+
+ \end{slide}
+
+ \begin{slide}
+
+ {\large\bf
+ Simulationen zum Ausscheidungsvorgang
+ }
+
+ \includegraphics[width=6.3cm]{pc_si-c_c-c.eps}
+ \includegraphics[width=6.3cm]{c_in_si_100.ps}
+
+ \footnotesize
+
+ \underline{Niedrige C-Konzentration ($V_1$)}:
+ 100 Dumbbell-Konfiguration
+ \begin{itemize}
+ \item dehnt Si-Si NN-Abstand auf 0.3 nm
+ \item Beitrag zum Si-C Peak bei 0.19 nm
+ \item erkl"art weitere Si-C Peaks (gestrichelte Linien)
+ \end{itemize}
+ $\Rightarrow$ C-Atome als erstes im erwarteten 3C-SiC-Abstand
+ \underline{Hohe C-Konzentration ($V_2$ und $V_3$)}:
+ \begin{itemize}
+ \item High amount of damage introduced into the system
+ \item Short range order observed but almost no long range order
+ \end{itemize}
+ $\Rightarrow$ Start of amorphous SiC-like phase formation\\
+ $\Rightarrow$ Higher temperatures required for proper SiC formation
\end{slide}
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